Re: [PATCH v2 5/7] arm64/efi: Use a semaphore to protect the EFI stack and FP/SIMD state
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2025-09-05 13:55:11
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linux-efi, lkml
On Fri, 5 Sept 2025 at 15:44, Peter Zijlstra [off-list ref] wrote:
On Fri, Sep 05, 2025 at 03:30:41PM +0200, Ard Biesheuvel wrote:quoted
From: Ard Biesheuvel <ardb@kernel.org> Replace the spinlock in the arm64 glue code with a semaphore, so that the CPU can preempted while running the EFI runtime service.Gotta ask, why a semaphore and not a mutex?
Because mutex_trylock() is not permitted in interrupt context.